The low-cost carrier says the change is to stop families from being split up on busy flights, as it causes delays to departures. Ryanair has announced plans to make it mandatory for adults travelling with children under 12 to buy reserved seating.The low-cost carrier says the change, which will come into force from 1 September, is to prevent young families from being split up on busy planes and delaying departures. Although adults will have to stump up and pay an £8 premium for their plane seat, their children's reservations will be free of charge. In a statement, the company said it had to introduce mandatory reservations because many adults travelling with young children were not choosing their preferred seats in advance. Source